The present invention relates to a power supply source control apparatus for a satellite broadcast receiver, and more particularly, to a power supply source control apparatus capable of preventing a power supply source from being damaged when a low noise unit and an antenna direction adjuster, which are installed outdoors to receive a satellite broadcast, are shorted or misoperate.
Due to increased use of satellite broadcast systems, there have been a lot of development activities recently in this field. In particular, as one example of a polarization control method for a satellite broadcast receiver, vertical and horizontal polarized waves are controlled by varying the supply voltage for a low noise unit. Another method is to make the supply voltage for the low noise unit fixed and provide an independent power supply source for controlling the vertical and horizontal polarized waves. It has become necessary to have a power supply source switching unit for the low noise unit or a power supply source switching unit for exclusive use in controlling only the vertical and horizontal polarized waves.
Referring to FIG. 1, a conventional satellite broadcast receiver will be described. A parabolic antenna 11 for receiving radio waves from a broadcasting satellite is connected to low noise booster unit 12 for amplifying weak radio waves up to necessary signal levels. An antenna direction adjuster 13 adjusts the direction of parabolic antenna 11 according to the position of the satellite. A satellite broadcast receiver 14 for supplying power to the respective satellite broadcast receiving facilities and for processing a signal transmitted from low noise booster unit 12 is connected to a television receiver 15.
Parabolic antenna 11, which is an outdoor dish-shaped antenna, receives the radio waves from the broadcasting satellite and supplies the received radio waves to the low noise unit 12. Low noise booster unit 12 amplifies and frequency-converts the weak satellite broadcast signals received from parabolic antenna 11 into signals having the necessary signal levels, and then outputs the converted signal through a cable, such as a coaxial cable. Antenna direction adjuster 13 adjusts the direction of parabolic antenna 11 according to the position of the satellite. Satellite broadcast receiver 14 receives the satellite broadcast signals from low noise booster unit 12 and converts the received satellite broadcast signals into those having formats suitable for display on television receiver 15. Television receiver 15 displays the signals supplied from satellite broadcast receiver 14 on a screen. In FIG. 1, parabolic antenna 11, low noise booster unit 12 and antenna direction adjuster 13 are installed outdoors, while satellite broadcast receiver 14 and television receiver 15 are installed indoors. The satellite broadcast facilities which are installed outdoors receive their power from the satellite broadcast receiver 14.
The low noise unit 12, which is installed outdoors as described above, is connected to a tuner in the satellite broadcast receiver through a cable. Also, the low noise booster unit 12 and the antenna direction adjuster 13 receive the power and control signals from satellite broadcast receiver 14 through the cable. Thus, if a short circuit occurs in the low noise booster unit 12 or the antenna direction adjuster 13, overcurrent flows into the satellite broadcast receiver 14, thereby causing the satellite broadcast receiver to be damaged.